可见光照射下SiW12O4-40/Resin光催化剂活化H2O2降解染料的研究

将杂多酸(SiW12O4-40)负载到阴离子交换树脂上,得到SiW12O4-40/Resin(SWR)固相光催化剂,在可见光的照射下,可以有效地活化H2O2降解染料.以罗丹明B(Rhodamine B,RhB)为模型化合物,研究了不同条件下RhB的降解动力学,以及降解过程中其UV-vis光谱及体系的总有机碳(Total Organic Carbon,TOC)变化情况,结果表明RhB的共轭芳环结构被破坏,矿化率为24.2%.其它染料如孔雀绿(Malachite Green,MG)和吖啶橙(Acridine Orange,AO)等也可以被降解和矿化.催化剂的循环实验表明SWR固相光催化剂易于分离,并且具有良好的稳定性,可以重复利用.     

Keggin型铜取代磷钨杂多阴离子可见光催化降解罗丹明B

以Keggin型铜取代杂多阴离子PW11O39Cu(Ⅱ)(H2O)5-[PW11Cu]为可见光催化剂,有机染料罗丹明B(RhB)为模型污染物,研究了在可见光照射下PW11Cu对RhB的可见光催化降解作用,提出了PW11Cu可见光催化作用的反应机理,同时考察了RhB初始浓度、PW11Cu初始浓度和溶液pH值对RhB光催化降解速率的影响。 实验结果表明,含有15.6 μmol/L PW11Cu+10 μmol/L RhB的水溶液在可见光照射下反应80 min,RhB的降解率达100%,总有机碳去除率约33%。 RhB的可见光催化降解服从准一级动力学方程,在RhB初始浓度为20、30和40 μmol/L的情况下,其表观一级速率常数分别为3.1×10-2、2.0×10-2和1.5×10-2 min-1。     

可见光照射下SiW12O404-/Resin光催化剂活化可见光照射下SiW12O404-/Resin光催化剂活化H2O2降解染料的研究

将杂多酸(SiW₁₂O₄₀^4-)负载到阴离子交换树脂上, 得到SiW₁₂O₄₀^4-/Resin (SWR)固相光催化剂, 在可见光的照射下, 可以有效地活化H₂O₂降解染料. 以罗丹明B (Rhodamine B, RhB)为模型化合物, 研究了不同条件下RhB的降解动力学, 以及降解过程中其UV-vis光谱及体系的总有机碳(Total Organic Carbon, TOC)变化情况, 结果表明RhB的共轭芳环结构被破坏, 矿化率为24.2%. 其它染料如孔雀绿(Malachite Green, MG)和吖啶橙(Acridine Orange, AO)等也可以被降解和矿化. 催化剂的循环实验表明SWR固相光催化剂易于分离, 并且具有良好的稳定性, 可以重复利用.     

可见光照射下SiW12O404-/Resin光催化剂活化可见光照射下SiW12O404-/Resin光催化剂活化H2O2降解染料的研究

将杂多酸(SiW₁₂O₄₀^4-)负载到阴离子交换树脂上, 得到SiW₁₂O₄₀^4-/Resin (SWR)固相光催化剂, 在可见光的照射下, 可以有效地活化H₂O₂降解染料. 以罗丹明B (Rhodamine B, RhB)为模型化合物, 研究了不同条件下RhB的降解动力学, 以及降解过程中其UV-vis光谱及体系的总有机碳(Total Organic Carbon, TOC)变化情况, 结果表明RhB的共轭芳环结构被破坏, 矿化率为24.2%. 其它染料如孔雀绿(Malachite Green, MG)和吖啶橙(Acridine Orange, AO)等也可以被降解和矿化. 催化剂的循环实验表明SWR固相光催化剂易于分离, 并且具有良好的稳定性, 可以重复利用.     

Keggin型铬取代杂多阴离子/阴离子交换树脂的可见光催化性能

将Keggin型铬取代磷钨杂多阴离子PW11O39Cr(Ⅲ)(H2O)4-(PW11Cr)负载于弱碱性阴离子交换树脂D301R表面,制备了固体光催化剂PW11Cr/D301R,并以模型污染物罗丹明B(RhB)的降解为探针评估了该催化剂的可见光催化活性,讨论了光催化反应机理,同时考察了催化剂剂量、溶液pH值和溶液中常见离子对RhB可见光催化降解反应的影响以及催化剂的稳定性。实验结果表明,当PW11Cr/D301R的剂量为100 mg时,10μmol/L RhB水溶液暴露在200 W金卤灯下进行照射,RhB完全降解所需的时间仅为30 min,比PW11Cr均相体系缩短了3倍;反应180 min总有机碳(TOC)去除率约为84%。催化剂剂量、溶液pH值和溶液中存在的Cl-、SO2-4和PO3-4对RhB光催化降解反应的速率均有一定影响。催化剂循环实验显示经循环使用7次后催化剂的活性几乎没有损失。     

Keggin型铬取代杂多阴离子/D301R可见光催化性能

将Keggin型铬取代磷钨杂多阴离子PW11O39Cr(Ⅲ)(H2O)4-(PW11Cr)负载于弱碱性阴离子交换树脂D301R表面,制备了固体光催化剂PW11Cr/D301R,并以模型污染物罗丹明B(RhB)的降解为探针评估了该催化剂的可见光催化活性,讨论了光催化反应机理,同时考察了催化剂剂量、溶液pH值和溶液中常见离子对RhB可见光催化降解反应的影响以及催化剂的稳定性。 实验结果表明,当PW11Cr/D301R的剂量为100 mg时,10 μmol/L RhB水溶液暴露在200 W金卤灯下进行照射,RhB完全降解所需的时间仅为30 min,比PW11Cr均相体系缩短了3倍;反应180 min总有机碳(TOC)去除率约为84%。 催化剂剂量、溶液pH值和溶液中存在的Cl-、SO2-4和PO3-4对RhB光催化降解反应的速率均有一定影响。 催化剂循环实验显示经循环使用7次后催化剂的活性几乎没有损失。     

可见光照射下SiW12O40^4-／Resin光催化剂活化H2O2降解染料的研究

将杂多酸（SiW12O40^4-）负载到阴离子交换树脂上，得到SiW12O40^4-／Resin（SWR）固相光催化剂，在可见光的照射下，可以有效地活化H2O2降解染料．以罗丹明B（RhodamineB，RhB）为模型化合物，研究了不同条件下RhB的降解动力学，以及降解过程中其UV—vis光谱及体系的总有机碳（Total Organic Carbon，TOC）变化情况，结果表明RhB的共轭芳环结构被破坏，矿化率为24．2％．其它染料如孔雀绿（Malacllite Green，MG）和吖啶橙（Acridine Orange，AO）等也可以被降解和矿化．催化剂的循环实验表明SWR固相光催化剂易于分离，并且具有良好的稳定性，可以重复利用．     

杂多酸型光催化剂降解染料的研究进展

如何有效地去除废水中的染料一直是材料和环境科学的热门方向。对比传统的吸附法、浓缩过滤法等,光催化降解染料技术由于其特有的环保性、简便性、安全性和无二次污染性等优点引起了更广泛的关注。众多光催化剂中,杂多酸因特殊的"笼形"结构、可"调谐"的电子性质、无毒性、富氧表面、价廉、出色的氧化还原能力等特点而具有巨大应用潜力。本文介绍了最近几年的杂多酸型光催化的研究进展,按方法将它们归类为改性法和负载法,并又细分它们为取代型杂多酸、改变反荷离子型杂多酸、有机无机改性法、硅酸盐负载法、二氧化钛负载法和石墨烯负载法。主要改进方向是提高杂多酸的水溶性、拓宽光吸收活性、增大比表面积、提高回收性等。对不同催化剂体系下的合成条件、催化机理等进行总结与分析,并展望了未来的发展趋势。     

超声强化Keggin型Fe-Mo-Zr杂多酸盐降解染料废水

合成了Fe-Mo-Zr杂多酸盐催化剂,并利用红外光谱(IR)和X射线衍射(XRD)对制得的产物进行了表征,研究了Fe-Mo-Zr杂多酸盐超声降解模拟酸性绿B(AGB)染料废水的效果.结果表明,合成的杂多酸盐具有Keggin型结构,催化剂的投加量、染料的初始浓度及初始pH值、超声频率及超声时间都对降解效果产生一定的影响.当染料浓度为10mg/L,催化剂的投加量为0.6g/L时,在pH为5.0的条件下,用40kHz超声辐射60min,降解率最高可达93.18%.通过动力学分析:降解反应符合一级反应动力学模型,速率常数随初始浓度的增加而减小.     

D301R树脂对Keggin型铁取代杂多阴离子的吸附性能研究

详细研究了D301R弱碱性阴离子交换树脂对Keggin型铁取代杂多阴离子PW11O39Fe(III)(H2O)4－ (PW11Fe)的吸附作用, 考察了不同pH和温度对吸附量和吸附速率的影响, 测定了不同温度下吸附的动力学曲线和吸附等温线, 提出吸附动力学模型和计算了吸附的热力学函数, 结果表明, 在pH 2～8的范围内, PW11Fe的吸附量随溶液pH值的升高而增加, 随溶液温度的升高而降低; 吸附动力学符合表面过程控制的准二级反应模型, 其速率常数k2在298 K时为 9.33×10－4 g•mg－1•min－1, 并随温度的升高而减小. 吸附等温线符合Freundlich吸附模型, 吸附热约为40 kJ•mol－1, 因此, 吸附为物理吸附.     

Unusual enhancement of H2 evolution by Ru on TaON photocatalyst under visible light irradiation

H2 evolution on TaON photocatalyst under visible light irradiation (420 nm < or = lambda < or = 500 nm) in an aqueous methanol solution is found to be remarkably enhanced by adding Ru as a noble-metal co-catalyst.     

吸附法制备CdS/HKLBT复合催化材料及其可见光制氢活性

采用吸附法制备了CdS和层状物的复合光催化材料CdS/HKLBT(吸附),并采用X射线衍射(XRD)、紫外-可见漫反射(DRS)、透射电子显微镜(TEM)等技术对其进行了表征和分析。实验对比了吸附法制备的复合材料与离子交换法制备材料活性差异,考察了CdS负载量对复合物制氢活性的影响.结果表明,表面复合也能明显提高CdS的可见光制氢活性,当CdS复合量为15%(质量分数)时活性最高,达到532μmol/h,与离子交换法制备的光催化剂的产氢速率接近;而过多CdS的负载造成载流子迁移的障碍,从而不利于活性的提高.     

银-溴化银/麦羟硅钠石可见光催化剂的制备及其光催化性能

利用离子交换法将AgBr负载到水热合成的麦羟硅钠石(magadiite,MD)载体上,通过光照还原生成新型Ag-AgBr/MD复合光催化剂;采用X射线衍射仪、扫描电镜、透射电镜分析了复合催化剂的结构,采用紫外-可见分光光度计评价了AgBr负载量和pH对复合催化剂可见光催化降解罗丹明(RhB)水溶液活性的影响.结果表明,随着AgBr负载量的增加,RhB的降解率先增大后减小,随pH的增大RhB的降解率减小.当n(AgNO3)∶n(MD)=2∶1,pH=9时,复合光催化剂具有较强的光吸收性能,且AgBr高度分散在载体MD表面,因而对RhB的光催化降解性能最高.     

An undoped, single-phase oxide photocatalyst working under visible light

A novel photocatalyst, PbBi2Nb2O9 has been discovered that shows high activities for degradation of organic pollutants, generation of photocurrent, and water decomposition into O2 or H2, all under visible right irradiation (lambda >/= 420 nm). This is the first example of an undoped, single-phase oxide photocatalyst that shows such reactivity. Its quantum yields are much higher than those for most of the previously reported materials, especially in water decomposition to generate oxygen (29%). Since it is an oxide, there is much less concern for stability under light irradiation.     

Nb and N co-doped TiO2 for a high-performance deNO x photocatalyst under visible LED light irradiation

By a facile and rapid microwave-assisted hydrothermal reaction at 190 °C for 30 min, niobium and nitrogen co-doping TiO₂ nanoparticles were prepared. The obtained samples were characterized by XRD, UV–Vis spectroscopy, EDX analysis, and BET measurements. To evaluate the photocatalytic activity, destruction of NO _x gas under the irradiation of several LED lamps with various wavelengths were carried out. Although co-doping of Nb with N into TiO₂ resulted in the decrement of the specific surface area, it was useful to improve the photocatalytic activity for the oxidative destruction of NO, probably due to the effective reduction of the anion vacancy in the lattice which acts as the recombination center of the photo-induced electrons and holes.     

A Novel Sr2CuInO3S p-type semiconductor photocatalyst for hydrogen production under visible light irradiation

A novel Sr2CuInO3 S oxysulfide p-type semiconductor photocatalyst has been prepared by solid state reaction method and it exhibits intriguing visible light absorption properties with a bandgap of 2.3 eV. The p-type semiconductor character of the synthesized Sr2CuInO3 S was confirmed by Hall efficient measurement and Mott-Schottky plot analysis. First-principles density functional theory calculations(DFT) and electrochemical measurements were performed to elucidate the electronic structure and the energy band locations. It was found that the as-synthesized Sr2CuInO3 S photocatalyst has appreciate conduction and valence band positions for hydrogen and oxygen evolution, respectively. Photocatalytic hydrogen production experiments under a visible light irradiation(λ420 nm) were carried out by loading different metal and metal-like cocatalysts on Sr2CuInO3 S and Rh was found to be the best one among the tested ones.     

A Novel Sr2CuInO3S p-type semiconductor photocatalyst for hydrogen production under visible light irradiation

A novel Sr2CuInO3 S oxysulfide p-type semiconductor photocatalyst has been prepared by solid state reaction method and it exhibits intriguing visible light absorption properties with a bandgap of 2.3 eV. The p-type semiconductor character of the synthesized Sr2CuInO3 S was confirmed by Hall efficient measurement and Mott-Schottky plot analysis. First-principles density functional theory calculations(DFT) and electrochemical measurements were performed to elucidate the electronic structure and the energy band locations. It was found that the as-synthesized Sr2CuInO3 S photocatalyst has appreciate conduction and valence band positions for hydrogen and oxygen evolution, respectively. Photocatalytic hydrogen production experiments under a visible light irradiation(λ420 nm) were carried out by loading different metal and metal-like cocatalysts on Sr2CuInO3 S and Rh was found to be the best one among the tested ones.     

Ag/TiO_2/freeze-dried graphene nanocomposite as a high performance photocatalyst under visible light irradiation

Ag/TiO_2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO_2 nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO_2 surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO_2 were oxidized to Ag2 O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO_2 surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO_2 showed the highest photocatalytic activity, which is related to high migration efficiency of photoinduced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of Rh B molecules during evaluation of photocatalytic performance was negligible.     

Photoreduction of CO_2 to methanol over Bi_2S_3/CdS photocatalyst under visible light irradiation

The Bi2S3,CdS and Bi2S3/CdS photocatalysts were prepared by direct reactions between their corresponding salt and thiourea in a hy- drothermal autoclave.The photocatalytic activities of these photocatalysts for reducing CO2 to CH3OH under visible light irradiation have been investigated.The results show that the photocatalytic activity and visible light response of Bi2S3 are higher than those of CdS.The Bi2S3 modification can enhance the photocatalytic activity and visible light response of CdS.The photocatalytic activity of Bi2S3/CdS hetero-junction photocatalyst was the highest and the highest yields of methanol was 613μmol/g when the weight proportion of Bi2S3 to CdS was 15%,which was about three times as large as that of CdS or two times of that of Bi2S3.